Fluorinated dye compounds for organic solar cells

ABSTRACT

Electronic or optoelectronic device comprising a first electrode, a second electro, and an active layer arranged between and in electrical connection with the first and the second electrode. The active layer comprises at least one dye compound, which comprises small-molecule organic solar cells.

RELATED APPLICATIONS

This application is related to provisional U.S. Application No.62/138,560 filed Mar. 26, 2015, which is incorporated by reference inits entirety.

BACKGROUND

Photovoltaic cells convert radiation, for example visible light, intodirect current (DC) electricity. Organic solar cells (OSC) are organicphotoelectric conversion devices which comprise conductive organicpolymers or organic small molecules, for light absorption, chargegeneration and charge transport. Organic dye compounds find use in manyapplications, including solar panels and photodetectors. They may alsobe part of larger systems comprising other organic electronic devices,such as organic light emitting diodes (OLEDs) and organic thin filmtransistors (OTFTs).

A common small-molecule OSC structure is formed by a transparentconducting oxide (TCO) electrode, typically Indium Tin Oxide (ITO), anorganic hole collecting layer (for example the doped polymer PEDOT:PSS),a photoactive layer, and the metallic contact, in some cases a thininterlayer of calcium or lithium fluoride. The photoactive layer isformed from a blend of donor and acceptor organic semiconductors.Typically, the acceptor semiconductor is a soluble fullerene derivativeand the donor semiconductor is a small-molecule organic dye compound.

Suitable dye compounds for small-molecule OSCs have been reported in theliterature, e.g. in Fitzner, R et al., Journal of the American ChemicalSociety, 2012, 134, 11064-11067, which is incorporated herein fully byreference. However, there is still a need for dye compounds for OSCswith improved properties.

SUMMARY

In one aspect, a small molecule compound of Formula (I):

T1a-T2a-(A1)_(m)-(B1)_(n)-P-(B2)_(n)-(A2)_(m)-T2b-T1b  (I)

where P can be an optionally substituted aryl group or an optionallysubstituted heteroaryl group; or P can be a group having the formula:-A1-P′-A2-, where P′ can be an optionally substituted aryl group or anoptionally substituted heteroaryl group. Each B1 and each B2,independently, can be an optionally substituted thiophene. Each A1 andeach A2, independently, can be an optionally substituted aryl group oran optionally substituted heteroaryl group.

T2a and T2b, independently, can have the formula:

T1a and T1b, independently, can have the formula:

where each R⁴, R⁵, R⁶, R⁷, and R⁸, independently, can be H, halo, alkyl,haloalkyl, alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl,heteroaryl, or acyl; each R⁹, independently, can be H, alkyl, orhaloalkyl.

Each n, independently, can be 0, 1, 2 or 3; each m, independently, canbe 1, 2, or 3.

In Formula (I), at least one of R⁴ to R⁸ is halo or haloalkyl; and whenR⁴ or R⁵ is fluoro, the other is not alkyl or haloalkyl, and when R⁷ orR⁸ is fluoro, the other is not alkyl or haloalkyl.

In another aspect, a small molecule compound of Formula (II):

(T1a)-(T2a-T2a)_(y)-(B1)_(x)-(A1)_(j)-(B2)_(x)-(T2b-T2b)_(y)-(T1b)  (II)

where each A1, independently, can be selected from the group consistingof

where each Q, independently, can be O or S; each R₀, independently, canbe H or alkyl.

Each B1 and each B2, independently, can be an optionally substitutedthiophene. Each T2a and each T2b, independently, can have the formula:

Each T1a and each T1b, independently, can have the formula:

where each R⁴, R⁵, R⁶, R⁷ and R⁸, independently, can be H, halo, alkyl,haloalkyl, alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl,heteroaryl, or acyl.

Each R⁹, independently, can be H, alkyl, or haloalkyl. j can be 1, 2, or3; each x, independently, can be 0, 1, or 2; each y, independently, canbe 1 or 2. In Formula (II), at least one of R⁴ to R⁸ is halo orhaloalkyl.

Dye molecules according to Formula II are of the center heteroarylvariety, where the center is optionally flanked by a number ofsubstituted or unsubstituted thiophenes, followed by a number ofsubstituted or unsubstituted fluorinated thiophene ending groups.

In another aspect, a small molecule compound of Formula (III):

(E)-(T2a-T2a)_(y)-(A2)_(z)-(P)_(x)-(A1)_(j)-(P)_(x)-(A2)_(z)-(T2b-T2b)_(y)-(E)  (III)

where each P, independently, can be an optionally substituted aryl groupor an optionally substituted heteroaryl group. Each A1 and each A2,independently, can be an optionally substituted aryl group or anoptionally substituted heteroaryl group.

Each T2a and each T2b, independently, can have the formula:

where each R⁴ and R⁵, independently, is H, halo, alkyl, haloalkyl,alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl, heteroaryl,or acyl. Each R⁹, independently, can be H, alkyl, or haloalkyl.

Each E, independently, can be selected from the group consisting of:

where each Q, independently, can be O or S; each R₀, independently, canbe H or alkyl. Each R₁₀, independently, can be halo, —NO₂, —N₃, —CN,—OR₀, or R₀. j can be 1, or 2; Each x, independently, can be 0, 1, or 2.Each y, independently, can be 1 or 2. Each z, independently, can be 0,1, or 2. In Formula (III), each A2, independently, is not A1; and atleast one of R⁴ or R⁵ is halo or haloalkyl.

In Formula (III), each A1, A2, T2a, T2b, P, E, j, x, y, and z areselected such that the small molecule compound is symmetric about A1.

In another aspect, a small molecule compound of Formula (IV):

(T1a)-(T2a)_(y)-(B1)_(x)-A3-(B2)_(x)-(T2b)_(y)-(T1b)  (IV)

wherein each A3, independently, can be selected from the groupconsisting of

each R₀₀, independently, can be H or alkyl;

each Ar, independently, is selected from the group consisting of:

where Aryl=an aryl group;

where HetAryl=a heteroaryl group;

where Aryl^(F)=a fluorinated aryl group;

where HetAryl^(F)=a fluorinated heteroaryl group;

where R^(F)=a fluorinated alkyl group;

where X═F, Cl, Br, I, OR₀, SR₀, NHR₀, NR₀R₀, or R₀;

where R₀═H or alkyl.

each B1 and each B2, independently, can be an optionally substitutedthiophene;

each T2a and each T2b, independently, can have the formula:

each T1a and each T1b, independently, can have the formula:

wherein each R⁴, R⁵, R⁶, R⁷, and R⁸, independently, can be H, halo,alkyl, haloalkyl, alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂,aryl, heteroaryl, or acyl;

each R⁹, independently, can be H, alkyl, or haloalkyl;

each x, independently, can be 0, 1, or 2;

each y, independently, can be 1 or 2;

provided that at least one of R⁴ to R⁸ can be halo or haloalkyl.

Dye molecules according to Formula III can be viewed as having a mergedmolecular structure of Formulas I and II.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an electro-optic device accordingto an embodiment of the current invention.

FIG. 1A shows the chemical structure of SDT[PT(1)]₂ (top), film opticalabsorption (bottom left) of BHJ film and J-V plot (bottom right) of anITO/MoO₃/SDT[PT(1)]₂:PC₇₁BM/ZnO-np/A1 device processed from achlorobenzene BHJ solution containing 0.4% 1,8-diiodooctane and a 60:40SDT[PT(1)]₂:PC₇₁BM blend ratio.

FIG. 2 shows the chemical structure of SDT[^(F)BT(1)]₂ (top), filmoptical absorption (bottom left) of BHJ film and J-V plot (bottom right)of an ITO/PEDOT:PSS/SDT[^(F)BT(1)]₂:PC₇₁BMZnO-np/A1 device processedfrom a o-xylene BHJ solution containing 0.4% 1,8-diiodooctane and a60:40 SDT[^(F)BT(1)]₂:PC₇₁BM blend ratio.

FIG. 3 shows the chemical structure of SDT[PT(2)]₂ (top), film opticalabsorption (bottom left) of BHJ film and J-V plot (bottom right) of anITO/MoO₃/SDT[PT(2)]₂:PC₇₁BM/A1 device processed from a chlorobenzene BHJsolution containing 0.4% 1,8-diiodooctane and a 60:40 SDT[PT(2)]₂:PC₇₁BMblend ratio.

FIG. 4 shows the chemical structure of SDT[^(F)BT(2)]₂ (top), filmoptical absorption (bottom left) of BHJ film and J-V plot (bottom right)of an ITO/PEDOT:PSS/SDT[^(F)BT(2)]₂:PC₇₁BM/A1 device processed from ao-xylene BHJ solution containing 2.0% 1-phenylnathalene and a 55:45SDT[^(F)BT(2)]₂:PC₇₁BM blend ratio.

FIG. 5 shows the chemical structure of SDT[PT(3)]₂ (top), film opticalabsorption (bottom left) of BHJ film and J-V plot (bottom right) of anITO/MoO₃/SDT[PT(3)]₂:PC₇₁BM/A1 device processed from a chlorobenzene BHJsolution containing 0.4% 1,8-diiodooctane and a 60:40 SDT[PT(3)]₂:PC₇₁BMblend ratio.

FIG. 6 shows the chemical structure of SDT[PT(4)]₂ (top), film opticalabsorption of BHJ film (bottom left) and J-V plot (bottom right) of anITO/MoO₃/SDT[PT(4)]₂:PC₇₁BM/A1 device processed from a chlorobenzene BHJsolution containing 0.4% 1,8-diiodooctane and a 60:40 SDT[PT(4)]₂:PC₇₁BMblend ratio.

FIG. 7 shows the chemical structure of SDT[^(F)BT(4)]₂ (top), filmoptical absorption of BHJ film (bottom left) and J-V plot (bottom right)of an ITO/PEDOT:PSS/SDT[^(F)BT(4)]₂:PC₇₁BM/ZnO/A1 device processed froma o-xylene BHJ solution containing 0.6% 1,8-diiodooctane and a 55:45SDT[^(F)BT(4)]₂:PC₇₁BM blend ratio.

FIG. 8 shows the chemical structure of SDT[^(FF)BT(4)]₂ (top), filmoptical absorption of BHJ film and J-V plot (bottom right) of anITO/PEDOT:PSS/SDT[^(FF)BT(4)]₂:PC₇₁BM/ZnO/A1 device processed from ao-xylene BHJ solution containing 0.6% 1-phenylnathalene and a 55:45SDT[^(FF)BT(4)]₂:PC₇₁BM blend ratio.

DETAILED DESCRIPTION

The present invention relates to dye compounds comprising at least onefluorinated thiophene unit, intermediates for their manufacture as wellas small-molecule organic solar cells comprising said dye compounds.

It is an object of the present invention to provide dye compoundsleading to improved conversion efficiency when used in an OSC. Moreparticularly, the purpose of an embodiment of the present invention isto provide dye compounds having a broad absorption spectrum,particularly in the visible and near-IR regions. The dye compounds of anembodiment of the present invention advantageously exhibit a high molarextinction coefficient. The inventive dye compounds can advantageouslyhave an improved long-term stability, for example, by showing improvedresistance to water contained in trace amounts in the devices. Theinventive dye compounds can advantageously show an improved bandgapbetween the LUMO level of the acceptor semiconductor and the HOMO of thedye compound. It is another objective to provide dye compounds that canlead to improved open-circuit voltages (V_(OC)), short-circuit densities(J_(SC)) and/or fill factors (FF). It is yet another objective toprovide dye compounds with improved pi-stacking, crystallinity,solubility and/or miscibility.

FIG. 1 is a schematic illustration of an electro-optic device 100according to an embodiment of the current invention. The electro-opticdevice 100 has a first electrode 102, a second electrode 104 spacedapart from the first electrode 102, and an active layer 106 disposedbetween the first electrode and the second electrode. The electro-opticdevice 100 can have multiple layers of active materials and/or layers ofmaterial between the electrodes and the active layer such as the layer108, for example.

The first electrode 102 and the second electrode 104 can beinterfacial/transport layers to facilitate charge extraction and twoconductive charge collecting electrodes, one or both of which may betransparent. The active layer 106 can include a photoactive layer. In anembodiment, the photoactive layer can include one or more dye compoundof the present invention comprising at least one fluorinated thiopheneunit. The photoactive layer can be formed from a blend of donor andacceptor organic semiconductors. In one embodiment, the donor organicsemiconductors is one or more dye compounds of the present inventioncomprising at least one fluorinated thiophene unit. One or both of theelectrodes 102 and 104 can be transparent electrodes in someembodiments.

In one aspect of the present invention, an electronic or optoelectronicdevice includes a first electrode; a second electrode proximate thefirst electrode with a space reserved therebetween; and an active layerarranged between and in electrical connection with the first and secondelectrodes. In some embodiments, the active layer includes one or moredye compound. In some embodiments, the dye compound comprises a smallmolecule compound of Formula (I), Formula (II), Formula (III), and/orFormula (IV), as provided below.

The term “aryl” used alone or as part of a larger moiety, refers tomono-, bi-, tri-, or larger aromatic hydrocarbon ring systems havingfive to thirty members. Aryl groups may be independently defined betweenany two endpoints within this range, so that a particular aryl group mayhave, for example, 5 to 24 members, 6 to 24 members, 6 to 14 members, 10to 30 members, and so forth. The term “aryl” may be used interchangeablywith the term “aryl ring”. “Aryl” also includes fused polycyclicaromatic ring systems in which an aromatic ring is fused to one or morerings. Examples include 1-naphthyl, 2-naphthyl, 1-anthracyl and2-anthracyl. Also included within the scope of the term “aryl”, as it isused herein, is a group in which an aromatic ring is fused to one ormore nonaromatic rings, such as in an indanyl, phenanthridinyl, ortetrahydronaphthyl, and including spiro compounds, such asspirobi[fluorene], where the radical or point of attachment is on thearomatic ring. The term “aralkyl” refers to an alkyl substituentsubstituted by an aryl group. The term “aryloxy” refers to an —O-arylgroup, such as, for example phenoxy, 4-chlorophenoxy and so forth.

The term “arylthio” refers to an —S-aryl group such as, for examplephenylthio, 4-chlorophenylthio, and so forth. The term “aryl” used aloneor as part of a larger moiety also refers to aryl rings that aresubstituted such as, for example, 4-chlorophenyl, 3,4-dibromophenyl andso forth. An aryl group may have more than one substituent, up to thetotal number of free substitution positions. For example, an aryl groupmay have 1, 2, 3, 4, 5 or more substituents. The substituents may thesame or different. Substituents on an aryl group include hydrogen,halogen, alkyl, alkenyl, nitro, hydroxyl, amino, alkylamino, alkoxy, andalkylthio, acyl, O-acyl, N-acyl, S-acyl as defined herein.

The term “aryl” is intended to denote a group which derives from anaromatic nucleus such as, in particular, a C₆-C₁₀ aromatic nucleus.Specific examples of such groups are phenyl, 1-tolyl, 2-tolyl, 3-tolyl,xylyl, 1-naphthyl and 2-naphthyl, in particular phenyl or naphthyl. Thearyl group can optionally be substituted, e.g. by halogen, alkyl, orcycloalkyl.

The term “heteroaryl”, used alone or as part of a larger moiety, refersto heteroaromatic ring groups having five to thirty members, in whichone or more ring carbons (1 to 6, 1 to 4, 1 to 3, 1 to 2, or 1), areeach replaced by a heteroatom such as N, O, S, or Si. Heteroaryl groupsmay be independently defined between any two endpoints within thisrange, so that a particular heteroaryl group may have, for example, 5 to24 members, 6 to 24 members, 6 to 14 members, 10 to 30 members, and soforth. Examples of heteroaryl rings include 2-furanyl, 3-furanyl,N-imidazolyl, 2-imidazolyl, 4-imidazolyl, 5-imidazolyl, 3-isoxazolyl,4-isoxazolyl, 5-isoxazolyl, 2-oxadiazolyl, 5-oxadiazolyl, 2-oxazolyl,4-oxazolyl, 5-oxazolyl, 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 1-pyrazolyl,3-pyrazolyl, 4-pyrazolyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrimidyl,4-pyrimidyl, 5-pyrimidyl, 3-pyridazinyl, 2-thiazolyl, 4-thiazolyl,5-thiazolyl, 5-tetrazolyl, 2-triazolyl, 5-triazolyl, 2-thienyl,3-thienyl, carbazolyl, benzimidazolyl, benzothienyl, benzofuranyl,indolyl, quinolinyl, benzotriazolyl, benzothiazolyl, benzooxazolyl,benzimidazolyl, isoquinolinyl, indazolyl, isoindolyl, acridinyl,benzoisoxazolyl. Other specific examples include thiophene, pyrrole,furan, phosphole, benzodithiophene, spirothiophene, bithiophene,terthiophene, thienothiophene, dithienothiophene, benzothiophene,isobenzothiophene, benzodithiophene, cyclopentadithiophene,silacyclopentadiene, silacyclopentadienebithiophene, indole, benzene,naphthalene, anthracene, perylene, indene, fluorene, pyrene, azulene,pyridine, oxazole, thiazole, thiazine, pyrimidine, pyrazine, imidazole,benzoxazole, benzoxadiazole, benzothiazole, benzimidazole, benzofuran,isobenzofuran, thiadiazole, dithienopyrrole, dithienophosphole, andcarbazole 9,9-RR′-9H-fluorene, 9-R-9H-carbazole,3,3′-RR′silylene-2,2′-bithiophene,3,3′RR′-cyclopenta[2,1-b:3,4-b′]-dithiophene where R and R′═C₁-C₃₀ alkylor C₆-C₃₀ aryl. Also included within the scope of the term “heteroaryl”,as it is used herein, is a group in which a heteroaromatic ring is fusedto one or more aromatic or nonaromatic rings, including spiro compounds,where the radical or point of attachment is on the heteroaromatic ring.Examples include tetrahydroquinolinyl, tetrahydroisoquinolinyl,pyrido[3,4-d]pyrimidinyl, spirobi[dibenzo[b,c]silole],spirobi[cyclopenta[1,2-b:5,4-b′]dithiophene], orspirobi[silolo[3,2-b:4,5-b′]dithiophene]. The term “heteroaryl” may beused interchangeably with the term “heteroaryl ring” or the term“heteroaromatic.” The term “heteroaralkyl” refers to an alkyl groupsubstituted by a heteroaryl, such as, for example, 2-pyridylmethyl,3-pyridylmethyl, 1-imidazolomethyl, 2-imidazolomethyl and so forth. Theterm “heteroaryloxy” refers to an —O-heteroaryl group. The term“heteroarylthio” refers to an —S-aryl group. A heteroaryl group may havemore than one substituent, up to the total number of free substitutionpositions. For example, a heteroaryl group may have 1, 2, 3, 4, or 5substituents. The substituents may the same or different. Substituentson a heteroaryl group include hydrogen, halogen, alkyl, alkenyl, nitro,hydroxyl, amino, alkylamino, alkoxy, and alkylthio, acyl, O-acyl,N-acyl, S-acyl as defined herein.

The term “heteroaryl” is intended to denote in particular a cyclicaromatic group made up of 3, 4, 5, 6, 7 or 8 atoms, at least one ofwhich is a hetero atom. The hetero atom is often chosen from B, N, O,Si, P and S. It is more often chosen from N, O and S. Specific examplesof such heteroaryls are pyridine, pyrimidine, thiophene, thiazole,quinoline, isoquinoline, isoxazole, pyrazole, imidazole, furan, dioxane.The heteroaryl group can optionally be substituted, e.g. by halogen,alkyl, or cycloalkyl.

The term “alkyl” is intended to denote in particular a linear orbranched alkyl or a cycloalkyl group comprising from 1 to 20 carbonatoms, preferably 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms. Specificexamples of such substituents are methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, 2-hexyl,n-heptyl, n-octyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl andcycloheptyl. If not further specified, the term “alkyl” is intended todenote n-alkyl, e.g. C₆H₁₃ is intended to denote n-C₆H₁₃. The alkyl orcycloalkyl group can optionally be substituted, e.g. by halogen.Halogen-substituted alkyl groups can also be referred to as “haloalkyl”groups, and include fluoro-substituted alkyl groups, i.e., “fluoroalkyl”groups. The term fluoroalkyl includes perfluoroalkyl.

The term “alkylidene” is intended to denote in particular a C₂ to C₇alkylene group, including a vinylidene group, wherein the alkylidenegroup preferably comprises a bridge of 2, 3, 4, 5, or 6 carbon atoms,more preferably 2 carbon atoms. The alkylidene group can optionally besubstituted, e.g. by halogen, alkyl, or cycloalkyl.

In some embodiments, the invention includes a small molecule compound ofFormula (I):

T1a-T2a-(A1)_(m)-(B1)_(n)-P-(B2)_(n)-(A2)_(m)-T2b-T1b  (I)

In Formula (I), P can be an optionally substituted aryl group or anoptionally substituted heteroaryl group, or P can be a group having theformula: -A1-P′-A2-, wherein P′ is an optionally substituted aryl groupor an optionally substituted heteroaryl group. Each B1 and each B2,independently, can be an optionally substituted thiophene. Each A1 andeach A2, independently, can be an optionally substituted aryl group oran optionally substituted heteroaryl group.

T2a and T2b, independently, can have the formula:

T1a and T1b, independently, can have the formula:

Each R⁴, R⁵, R⁶, R⁷, and R⁸, independently, can be H, halo, alkyl,haloalkyl, alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl,heteroaryl, or acyl. Each R⁹, independently, can be H, alkyl, orhaloalkyl. Each n, independently, can be 0, 1, 2 or 3. Each m,independently, can be 1, 2, or 3.

In Formula (I), at least one of R⁴ to R⁸ is halo or haloalkyl, and whenR⁴ or R⁵ is fluoro, the other is not alkyl or haloalkyl, and when R⁷ orR⁸ is fluoro, the other is not alkyl or haloalkyl.

Thus, in some embodiments, the compounds of Formula (I) can include adithiophene moiety; at least one substituent within the dithiophenemoiety can be a fluorinated substituent (e.g., fluoro or fluoroalkyl).

In some embodiments, each of R⁴ to R⁸, independently, is H, fluoro,alkyl, or fluoroalkyl.

In some embodiments, either (i) each R⁶, independently, is alkyl, and atleast one of R⁴, R⁵, R⁷, and R⁸ is fluoro, and the remaining of R⁴ to R⁸are H or fluoro; or (ii) each R⁶, independently, is fluoro or haloalkyl,and each R⁴, R⁵, R⁷, and R⁸, independently, is H or alkyl.

In some embodiments, each T1a, T2a, A1, B1, B2, A2, T2b, T1b, n and mare selected such that the small molecule compound is symmetric about P.

In some embodiments, P or P′ is selected from the group consisting of

where each R₀₀, independently, is H or alkyl; and each i is 0, 1, 2, or3.

In some embodiments, each A1 and each A2, independently, is selectedfrom the group consisting of:

where each Q, independently, is O or S; and each R₀, independently, is Hor alkyl.

In some embodiments, P is selected from the group consisting of

where each R₀₀, independently, is H or alkyl; and each i is 0, 1, 2, or3; and

each A1 and each A2, independently, is selected from the groupconsisting of:

where each Q, independently, is O or S; each R₀, independently, is H oralkyl; and where each T1a, T2a, A1, B1, B2, A2, T2b, T1b, n and m areselected such that the small molecule compound is symmetric about P.

In some embodiments, P or P′ has the formula:

where X is C, Si, or Ge; and each R₀₀, independently, is H or alkyl.

In some embodiments, each A1 and each A2, independently, is selectedfrom the group consisting of:

In some embodiments, each n is 0.

In some embodiments, the small molecule compound has the formula:

wherein

each Y and each Z, independently, is N or CR³;

each R³, independently, is H, F, alkyl, or haloalkyl; and

provided that Y-Z is not CH—CH.

In another aspect, a small molecule compound of Formula (II):

(T1a)_(z)-(T2a-T2a)_(y)-(B1)_(x)-(A1)_(j)-(B2)_(x)-(T2b-T2b)_(y)-(T1b)_(z)  (II)

In Formula (II), each A1, independently, can be selected from the groupconsisting of

where each Q, independently, can be O or S; and each R₀, independently,can be H or alkyl. Each B1 and each B2, independently, is an optionallysubstituted thiophene. Each T2a and each T2b, independently, can havethe formula:

Each T1a and each T1b, independently, can have the formula:

Each R⁴, R⁵, R⁶, R⁷, and R⁸, independently, can be H, halo, alkyl,haloalkyl, alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl,heteroaryl, or acyl. Each R⁹, independently, can be H, alkyl, orhaloalkyl. j can be 1, 2, or 3. Each x, independently, can be 0, 1, or2. Each y, independently, can be 1 or 2. Each z, independently, can be0, 1, or 2.

In Formula II, at least one of R⁴ to R⁸ is halo or haloalkyl.

In another aspect, a small molecule compound of Formula (III):

(E)-(T2a-T2a)_(y)-(A2)_(z)-(P)_(x)-(A1)_(j)-(P)_(x)-(A2)_(z)-(T2b-T2b)_(y)-(E)  (III)

In Formula (III), each A1 and each A2, independently, can be selectedfrom the group consisting of

where each Q, independently, can be O or S; and each R₀, independently,can be H or alkyl; provided that A1 is different from A2; and each P,independently, can be selected from the group consisting of:

where each R₀₀, independently, is H or alkyl; and each i is 0, 1, 2, or3; and each T2a and each T2b, independently, can have the formula:

Each R⁴, and R⁵, independently, can be H, alkyl, haloalkyl, alkoxy,alkenyl, alkynyl, thioalky, —NHR⁹, —N(R⁹)₂, aryl, heteroaryl, or acyl.Each R⁹, independently, can be H, alkyl, or haloalkyl. j can be 1, 2, or3. Each x, independently, can be 0, 1, or 2. Each y, independently, canbe 1 or 2. Each z, independently, can be 0, 1, or 2; and each Eindependently can be selected from the group consisting of:

where each Q, independently, can be O or S; each R₀, independently, canbe H or alkyl; and each R₁₀, independently, can be halo, —NO₂, —N₃, —CN,—OR₀, or R₀.

In another aspect, a small molecule compound of Formula (IV):

(T1a)-(T2a)_(y)-(B1)_(x)-A3-(B2)_(x)-(T2b)_(y)-(T1b)  (IV)

In Formula (IV), each A3, independently, can be selected from the groupconsisting of

where each R₀₀, independently, can be H or alkyl; each Ar,independently, is selected from the group consisting of:

where Aryl=an aryl group;

where HetAryl=a heteroaryl group;

where Aryl^(F)=a fluorinated aryl group;

where HetAryl^(F)=a fluorinated heteroaryl group;

where R^(F)=a fluorinated alkyl group;

where X═F, Cl, Br, I, OR₀, SR₀, NHR₀, NR₀R₀, or R₀;

where R₀═H or alkyl;

-   -   where each B1 and each B2, independently, can be an optionally        substituted thiophene; each T2a and each T2b, independently, can        have the formula:

where each T1a and each T1b, independently, can have the formula:

where each R⁴, R⁵, R⁶, R⁷, and R⁸, independently, can be H, halo, alkyl,haloalkyl, alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl,heteroaryl, or acyl; each R⁹, independently, can be H, alkyl, orhaloalkyl; each x, independently, can be 0, 1, or 2; each y,independently, can be 1 or 2; and provided that at least one of R⁴ to R⁸can be halo or haloalkyl.

Some examples of compounds according to Formula (I) include:

Some additional examples of compounds according to Formula (I) include:

R₁ R₂ R₃ R₄ R₅ 1 H H F F C₆H₁₃ 2 F F H H C₆H₁₃ 3 H C₆H₁₃ H C₆H₁₃ CF₃ 4 HH H F C₆H₁₃

The compounds according to Formula (I) and Formula (II) can beadvantageously prepared from fluorinated thiophene precursors. Suchprecursors include fluorinated dithiophene compounds, such as, forexample, compounds selected from:

where X is selected from the group consisting of B(OR₂), SnR₃, and SiR₃,and where R is independently alkyl, alkylidene, aryl, or heteroaryl.These dithiophene compounds can be used in coupling reactions to preparecompounds of Formula (I) or Formula (II), or other compounds, e.g., byuse in reactions that form a covalent bond between two different ringsystems.

These processes for the preparation of compounds of Formula (I) or (II)are generally performed in presence of a solvent. Examples of suitablesolvents include but are not limited to hydrocarbons (e.g. toluene),alcohols (e.g. tert-butanol), acetonitrile, tetrahydrofuran, dioxane,dimethylformamide, dimethylacetamide, or mixtures thereof. The processesare usually performed under inert atmosphere, i.e., under an atmospherewhich is virtually free of oxygen, and in a solvent which is virtuallyfree of dissolved oxygen. The solvent is usually degassed by passingnitrogen through the reaction mixture or by performing at least onefreezing-thawing cycle under vacuum. Other methods for providingsolvents that are virtually free of dissolved oxygen are known.

The coupling reactions can advantageously be carried out at atemperature in the range from 0 to 150° C., preferably in the range from50 to 100° C.

Coupling reactions wherein X is SnR₃ are preferably carried out indehydrated solvents, such as dehydrated dioxane. SnR₃ is preferablytrialkyltin, for example, tributyltin or trimethyltin. LiCl can be addedto the reaction mixture.

Coupling reactions wherein X is SiR₃ are preferably carried out in thepresence of fluoride ions. Fluoride salts, for example,tetrabutylammonium fluoride, are a suitable source of fluoride ions.Also preferably, SiR₃ can be SiMe₃, Si(iso-Pr)₃ or SiEtCI₂.

The coupling reactions are advantageously carried out in the presence ofa transition-metal catalyst.

Suitable examples of transition metal catalysts aretris(dibenzylideneacetone)dipalladium(0), Pd(Ph)₄, Pd(OAc)₂ or PdCl₂.Most preferred is Pd(Ph)₄.

The coupling reactions can advantageously be carried out in the presenceof one or more phosphorus-containing ligands and/or one or more bases.Suitable examples of phosphorus-containing ligands aretriphenylphosphine and2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl. Suitable examplesfor bases are hydroxides, phosphates, alkoxides and carbonates ofelements of the group 1 or group 2 elements, e.g., sodium hydroxide,cesium carbonate, potassium phosphate or potassium tert-butoxide.Advantageously, these bases can be used in the form of an aqueoussolution, more particularly a solution in water.

The compounds of the present invention may be further isolated, forinstance by column chromatography, preferably by high pressure liquidchromatography (HPLC).

Examples

Dye Compounds

Dye Compound 1, SDT[PT(3)]₂

A flask was flushed with nitrogen and charged with SDTBr2 (5 g, 8.9mmol) and THF (43 ml). The system was cooled down to −78° C. and n-BuLi(7.8 ml of a 2.5 M solution in THF) was added slowly. After stirring for30 minutes, tributyltinchloride (4.8 ml, 17.8 mmol) was added slowly.The temperature of the system was allowed to come to ambient temperatureand the mixture was stirred overnight. The mixture was poured intotoluene and washed with water and brine. The obtained organic layer wasdried over MgSO₄ and the solvent was removed using a rotary evaporator.A green oil (8.9 g, 8.9 mmol) was obtained.

A flask was charged with PTBr2 (5.78 g, 19.6 mmol) and 20 mL toluene andwas flushed with nitrogen for 30 minutes. SDT(SnBu₃)₂ (8.87 g, 9 mmol)was dissolved in 25 ml toluene and this mixture was added to the flask.After flushing for another 30 minutes with nitrogen, the catalystPd(PPh₃)₄ (0.6 g, 0.54 mmol) was added. The flask got closed and heatedto 110° C. in the darkness for two days. After cooling to ambienttemperature, the reaction mixture was poured into methanol, filtered andwashed with methanol, acetone and hexanes. The collected solid waswashed again with hexanes, filtered and the rest of solvent was removedusing a rotary evaporator. A green solid was obtained (7.6 g, 9 mmol).

A flask was charged with BrPT-SDT-PTBr (0.85 g, I mmol), Bithiophene1—SnBu₃ (1.59 g, 2.3 mmol) and 5 mL toluene and was flushed withnitrogen for 30 minutes. Pd(PPh₃)₄ (0.09 g) was added. The flask wasclosed and heated to 110° C. in the darkness for two days. After coolingto ambient temperature, the reaction mixture was poured into methanol,filtered and washed with methanol, acetone and hexanes. The resultingsolid was washed again with hexanes, filtered and the rest of thesolvent was removed using a rotary evaporator to yield 1.5 g (1.0 mmol)of Dye Compound 1, SDT[PT(3)]₂.

Bithiophene 1—SnBu₃

3-hexyl-2-iodo-thiophene

26.7 g (178 mmol, 1.50 eq) sodium iodide was dissolved in a mixture ofAcOH (150 ml) and acetonitrile (150 ml) and cooled down with an icebath. To this solution, 19.0 g (143 mmol, 1.20 eq) N-chlorosuccinimidewere added in one portion and stirring continued for 15 min. Next, 20.0g (118 mmol, 1.00 eq) 3-hexyl-thiophene were added, the reaction mixturestirred for 15 min. under ice-cooling and 4 h at room temperature. Thesolution was quenched with saturated Na₂S₂O₃-sol. and extracted withMTBE (methyl tert-butylether). The organic layer was washed once againwith Na₂S₂O₃-sol., three times with 1 M NaOH solution and once withbrine, dried over Na₂SO₄ and evaporated. Having a lower boiling point asthe product, all impurities were distilled off under reduced pressure(up to bp 100° C. at 2 mbar). The residue was filtered through silicagel with n-hexane to afford a colorless oil (27.9 g, 80%). MS=294.

3-hexyl-2-(trifluoromethyl)thiophene

A flask with 36.1 g (190 mmol, 2.00 eq) water-free CuI was evacuated andpurged with argon several times. A solution of 27.9 g (94.8 mmol, 1.00eq) 3-hexyl-2-iodothiophene and 24.0 ml (190 mmol, 2.00 eq) methyl2,2-difluoro-2-fluorosulfonylacetate in 250 ml dimethylformamide DMF wasadded and the reaction mixture stirred at 90° C. for 24 h. 6.00 ml (47.4mmol, 0.50 eq) methyl-2,2-difluoro-2-fluorosulfonylacetate was added andstirring continued for another day at 90° C. After cooling down to roomtemperature the reaction mixture was diluted with water and MTBE andfiltered. The organic layer was washed once with water and twice withbrine, dried over Na₂SO₄ and the solvent removed under reduced pressure.The residue was purified by distillation to obtain a colourless oil(14.9 g, 63%, bp: 75-78° C. at 3 mbar).

2-[4-hexyl-5-(trifluoromethyl-2-thienyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

A solution of 13.8 g (58.4 mmol, 1.00 eq)3-hexyl-2-(trifluoromethyl)thiophene was cooled down to −78° C. and 25.7ml (64.3 mmol, 1.10 eg, 2.50 mol/l) n-BuLi was added dropwise. After 30min, 13.1 g (70.1 mmol, 1.20 eq)2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane was added andstirring continued for 30 min. The cooling bath was removed and thereaction mixture stirred over night at room temperature. It was quenchedwith water and extracted three times with EtOAc. The combined organiclayers were dried over Na₂SO₄ and evaporated. The crude product waspurified by column chromatography (dichloromethane/n-hexane 1:4). A paleyellow oil was obtained (11.6 g, 55%).MS=362.3-hexyl-5-(3-hexyl-2-thienyl)-2-(trifluoromethyl)thiophene.

7.90 g (32.0 mmol, 1.00 eq) 2-bromo-3-hexyl-thiophene, 11.6 g (32.0mmol, 1.00 eq)2-[4-hexyl-5-(trifluoro-methyl)-2-thienyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolaneand 11.1 g (80.1 mmol, 2.50 eq) K₂CO₃ were dissolved in a mixture of THF(100 ml) and water (100 ml). This solution was degassed with argon priorto the addition of 1.10 g (1.60 mmol, 0.05 eq) PdCl₂(PPh₃)₂ and stirredover night at 50° C. The reaction mixture was diluted with MTBE, washedtwice with water and once with brine, dried over Na₂SO₄ and the solventsremoved under reduced pressure. The residue was filtered through silicagel with n-hexane. All impurities with a lower boiling point wereremoved by kugelrohr distillation to afford a colourless oil (5.48 g,43%). MS=402.

Bithiophene 1—SnBu₃

A flask was flushed with nitrogen and charged with3,4′-dihexyl-5′-(trifluoromethyl)-2,2′-bithiophene (1.21 g, 3 mmol) and15 ml THF. The system was cooled down to 0° C. and then, 7.5 ml lithiumdiisopropylamine (0.5 M in THF) was slowly added dropwise. Afterstirring for 1 hour, SnBu₃Cl (0.95 ml, 3.75 mmol) was added dropwise.The reaction mixture was poured into hexane, washed with water and theresulting organic layer was dried over MgSO₄. The solvent was removed ona rotary evaporator. A yellow, brown liquid was obtained (1.76 g, 85%).

Employing techniques similar to those described above, additional tinreagents, such as those shown, can readily be prepared by one skilled inthe art.

R₁ R₂ R₃ R₄ R₅

1 H H F F C₆H₁₃ 2 F F H H C₆H₁₃ 3 H C₆H₁₃ H C₆H₁₃ CF₃ 4 H H H F C₆H₁₃

1 H H F F C₆H₁₃ 2 F F H H C₆H₁₃ 3 H C₆H₁₃ H C₆H₁₃ CF₃ 4 H H H F C₆H₁₃

Br^(F)BT(1)

¹H NMR (600 MHz, CDCl₃) δ=8.05 (d, J=4 Hz, 1H), 7.70 (d, J=12 Hz, 1H),7.27 (d, J=4 Hz, 1H), 2.73 (t, J=4 Hz, 2H), 1.67 (m, 2H), 1.45-1.3 (m,6H), 0.90 (m, 3H); ¹⁹F NMR (376 MHz, CDCl₃) δ=−103 (d, J=11 Hz, 1F),−133 (d, J=11 Hz, 1F), −140 (d, J=11 Hz, 1F).

Br^(F)BT(2)

¹H NMR (600 MHz, CDCl₃) δ=8.02 (d, J=4 Hz, 1H), 7.68 (d, J=10 Hz, 1H),7.19 (d, J=4 Hz, 1H), 6.96 (s, 1H), 2.74 (t, J=8 Hz, 2H), 1.66 (m, 2H),1.44-1.28 (m, 6H), 0.90 (m, 3H).

Br^(F)BT(4)

¹H NMR (500 MHz, CDCl₃) δ=8.01 (dd, J=10 Hz, J=1 Hz, 1H), 7.23 (d, J=4Hz, 1H), 6.78 (d, J=4 Hz, 1H), 2.84 (t, J=7 Hz, 2H), 1.71 (p, J=8 Hz,2H), 1.44-1.29 (m, 6H), 0.90 (m, 3H).

Br^(FF)BT(4)

¹H NMR (500 MHz, CDCl₃) δ=8.16 (d, J=4 Hz, 1H), 7.22 (d, J=4 Hz, 1H),6.97 (s, 1H), 2.74 (t, 7 Hz, 2H), 1.66 (m, 2H), 1.4-1.2 (m, 6H), 0.91(m, 3H); ¹⁹F NMR (376 MHz, CDCl₃) δ=−120.3 (d, J=18 Hz, 1F), −126.5 (d,J=18 Hz, 1F), −132 (s, 1F).

SDT[^(FF)BT(4)]₂

¹H NMR (400 MHz, CDCl₃) δ=8.27 (t, J=4 Hz, 2H), 7.89 (m, 2H), 6.95 (d,2H), 6.75 (s, 2H), 2.62 (t, J=8 Hz, 4H), 1.63 (m, 4H), 1.49-1.25 (m,30H), 1.13 (m, 4H), 0.91 (m, 18H); ¹⁹F NMR (376 MHz, CDCl₃) δ=−127.4 (s,br, 4F), −132.4 (s, 2F).

R₁ R₂ R₃ R₄ R₅ 1 H H F F C₆H₁₃ 2 F F H H C₆H₁₃ 3 H C₆H₁₃ H C₆H₁₃ CF₃ 4 HH H F C₆H₁₃

SDT[^(F)BT(1)]₂

¹H NMR (400 MHz, CDCl₃) δ=8.35 (m, 2H), 8.05 (d, J=4 Hz, 2H), 7.75 (d,J=12 Hz, 2H), 7.27 (d, J=4 Hz, 2H), 2.74 (t, J=8 Hz, 4H), 1.66 (m, 4H),1.43-1.01 (m, 34H), 0.95-0.75 (m, 18H); ¹⁹F NMR (376 MHz, CDCl₃) δ=−107(m, 2F), −133 (d, J=15 Hz, 2F), −140 (d, J=15 Hz, 2F); MS-FD (m/z)1290.25 (M⁺), 645.14 (M²⁺)

SDT[^(F)BT(4)]₂

¹H NMR (400 MHz, CDCl₃) δ=8.34 (t, J=4 Hz, 2H), 7.98 (d, J=4 Hz, 2H),7.71 (d, J=12 Hz, 2H), 7.18 (d, J=4 Hz, 2H), 6.93 (s, 2H), 2.73 (t, J=8Hz, 2H), 1.66 (p, J=7 Hz, 4H), 1.45-1.04 (m, 34H), 0.91 (m, 6H), 0.83(m, 12H); ¹⁹F NMR (376 MHz, CDCl₃) δ=−107 (q, J=16 Hz), −132 (s). MS-FD(m/z) 1254.27 (M⁺), 627.15 (M²⁺).

Dye compound, 4-bromo-BODIPY-(2)

R₁ R₂ R₃ R₄ R₅ 2 F F H H C₆H₁₃ 5 H H H C₆H₁₃ CF₃ OHC-2 F F H H C₆H₁₃OHC-5 H H H C₆H₁₃ CF₃

3,4-difluoro-5′-hexyl-[2,2′-bithiophene]-5-carbaldehyde (OHC-2)

In a flame dried flask equipped with an addition funnel,3,4-difluoro-5′-hexyl-2,2′-bithiophene [2] (8.5 g, 29.7 mmol) wasdissolved in dry 1,2-dichloroethane (150 mL) and cooled to 0° C. TheVilsmeier reagent was prepared by adding POCl₃ (5.46 g, 35.6 mmol, 3.32mL) to DMF (3.3 g, 45 mmol, 3.43 mL) and the orange solution was addeddropwise via addition funnel. The reaction was then heated at 80° C. for20 hours. After cooling to room temperature, the reaction wasneutralized with saturated NaHCO₃. The aqueous portion was extractedwith DCM (3×100 mL) and the combined organics were washed with water andbrine, dried over Na₂SO₄, and concentrated in vacuo to give the crudeproduct, which was further purified by chromatography on silica gel (2%EtOAc/hexanes) to furnish a yellow solid (6.53 g, 20.8 mmol, 70% yield).¹H NMR (600 MHz, CDCl₃) δ=9.98 (s, 1H), 7.29 (d, J=3.6 Hz, 1H), 6.80 (d,J=3.6 Hz, 1H), 2.84 (t, J=7.5 Hz, 2H), 1.70 (quint, J=7.2 Hz, 2H),1.40-1.29 (m, 6H), 0.89 (t, J=6.6 Hz, 3H); ¹⁹F NMR (400 MHz, CDCl₃)δ=−127.02 (s, 2F).

4′-hexyl-5′-(trifluoromethyl)-[2,2′-bithiophene]-5-carbaldehyde (OHC-5)

OHC-5 was prepared in an analogous fashion to that reported for OHC-2.¹H NMR (400 MHz, CDCl₃) δ=9.89 (s, 1H), 7.69 (d, J=4 Hz, 1H), 7.28 (d,J=4 Hz, 1H), 7.16 (m, 1H), 2.71 (t, J=8 Hz, 2H), 1.63 (p, J=7 Hz, 2H),1.42-1.27 (m, 6H), 0.89 (m, 3H); ¹⁹F NMP (376 MHz, CDCl₃) δ=−53.8.

General BODYIPY Synthesis

To a stirring solution of appropriately substituted pyrrole (5 g, 52mmol) dissolved in DCM (100 mL) at 40° C. was added an acid chloride(heptanoyl, benzoyl, etc) (25 mmol) dropwise. Once the addition wascomplete the reaction was allowed to stir until it was deep red incolour (1-18 hours). At this time the reaction mixture was cooled toroom temperature and treated with Hunig's base (75 mmol) at a rate thatprevented excessive boiling of the solvent. After stirring for 30minutes the (now pale) reaction was treated with BF₃OEt₂ and heated at30° C. overnight. The next day the reaction mixture was diluted with DCMand washed repeatedly with water before drying with MgSO₄ andconcentrating in vacuo. The crude material was then dissolved in DCM andpassed through a plug of SiO₂ (eluting with DCM) and the red band withyellow/green emission was collected. Further purification was performedusing flash column chromatography 20-60% DCM in hexane.

4-bromo-BODIPY

The above compound was prepared according to the general BODIPYsynthesis described above using 2,4-dimethyl-pyrrole, and 4-bromobenzoylchloride. 11 NMR (400 MHz, CDCl₃) δ=7.64 (d, J=8 Hz, 2H), 7.18 (d, J=8Hz, 2H), 5.99 (s, 2H), 2.55 (s, 6H), 1.41 (s, 6H).

4-Bromo-BODIPY-(2)

4-bromo-BODIPY (0.412 g, 1.02 mmol),3,4-difluoro-5′-hexyl-[2,2′-bithiophene]-5-carbaldehyde [OHC-2] (0.71 g,2.25 mmol), p-toluenesulfonic acid monohydrate (0.1 g, 0.5 mmol) weredissolved in toluene (10 mL). Piperidine (1 mL) was added and thesolution heated to 120° C. The reaction was monitored by UV/Vis and wasstopped after the consumption of the starting material. After cooling,the solution was passed through a short silica plug, eluting withtoluene. The solvent was evaporated and the crude material was fused tosilica gel (10 g) and purified by flash chromatography (35%DCM/hexanes). The DCM was removed by rotary evaporation and theresultant solids were collected by gravity filtration, washed withhexanes and acetone, then dried in vacuo to yield the final product as apurple solid (350 mg, 0.35 mmol, 34% yield). ¹H NMR (600 MHz, CDCl₃)δ=7.65 (d, J=8.3 Hz, 2H), 7.43 (s, 4H), 7.23 (d, J=8.3 Hz, 2H), 7.13 (d,J=3.6 Hz, 2H), 6.74 (d, J=3.4 Hz, 2H), 6.59 (s, 2H), 2.83 (t, J=7.4 Hz,4H), 1.75-1.61 (m, 8H), 1.45 (s, 6H), 1.43-1.31 (m, 8H), 0.90 (t, J=6.8Hz, 6H). ¹⁹F NMR (376 MHz, CDCl₃) δ=−125.96 (s, 1F), −138.84 (q, J=34Hz, 1F). ¹¹B NMR (128 MHz, CDCl₃) δ=1.14 (t, J=34 Hz, 1B).

Device Fabrication and Measurements

The small molecule dyes described are useful in organic solar cellapplications. The bulk heterojunction (BHJ) device structure wasutilized to show the applicability of the dyes, although other devicestructures can be used. In the fabricated BHJ devices the photoactivelayer includes a blended film of the small molecule dye manufactured andan electron deficient/accepting molecule or polymer. As examples, theBHJ devices consisted of blended films with {6,6}-phenyl C71 butyricacid methyl ester (PC₇₀BM) acceptors.

A typical BHJ device structure includes the photoactive layer sandwichedbetween interfacial/transport layers to facilitate charge extraction andtwo conductive charge collecting electrodes, one of which istransparent. The devices fabricated were composed of the followinglayers; glass/ITO/PEDOT:PSS or MoOx/BHJ/ZnO-np/Al, where ITO is indiumtin oxide, PEDOT:PSS ispoly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate), MoOx ismolybdenum trioxide, ZnO-np is zinc oxide nanoparticles and Al isaluminum.

Films for devices were prepared on patterned ITO-coated glass substrates(Thin Film Devices Inc.) and served as the bottom transparentcharge-collecting electrode. The ITO substrates were cleaned bysonication in a soap solution, acetone, isopropanol followed drying witha nitrogen gas flow and baking in an oven. Cleaned ITO substrates wereexposed to a UV-ozone treatment for >30 min. and immediately used foreither a 25 nm spin coated PEDOT:PSS (Clevious P VP AL 4083) layer or a15 nm vacuum thermal deposited MoO₃ (99.98%, Sigma-Aldrich) layer.

The following BHJ films were prepared from ≥40 mg/ml chlorobenzene (CB)or o-xylene stock solutions of donor compounds and PC₇₁BM (Solenne Inc.)depending on the small molecule dye used. Stock solutions were mixed atvarious ratios and addition of high boiling additives to make theappropriate BHJ solutions. Filtered (0.45 μm PTFE) BHJ solutions werespun cast at various spin speed to control films thickness andimmediately annealed at the appropriate temperature for >5 minutes.ZnO-np films were then spun cast on top of the BHJ film from2-methoxyethanol stock solutions and did not required any additionalannealing. The organic solar cell devices were completed by thermaldeposition (<10⁻⁶ torr base pressure) of 120 nm Al top electrodes havinga 13.2 mm² area via a shadow mask.

Device performance was assessed from current density versus voltages(J-V) measurements acquired with a LabView controlled multiplexedKeithley source-measured unit under 100 mW/cm² illumination from aNewport 1600 W Xenon arc lamp. The illumination intensity was calibratedusing a Newport meter and calibrated 91150V reference cell. Allmeasurements were performed in inert atmosphere glovebox with <0.5 ppmoxygen. Optical absorption measurements were measured with a PerkinElmerLambda Spectrometer.

Performance characteristics of organic solar cell devices containing dyecompounds are shown in FIGS. 1A-8, and summarized in Table 1. Thefluorine substituents have effects on both the physical and electronicproperties of the small molecular dye compounds as observed bydifferences in solubility, film forming ability, film quality and deviceperformance. The effects on electronic properties are most evident inthe solar cell device parameters such as the V_(OC) in which up to −100mV differences are observed by the fluorine substituents.

TABLE 1 Solar cell parameters of example devices with small moleculardye compounds. J_(SC) (mA cm⁻²) V_(OC) (mV) Fill Factor PCE (%)SDT[PT(1)]₂ 10.1 832 0.55 4.7 SDT[^(F)BT(1)]₂ 10.7 781 0.49 4.1SDT[PT(2)]₂ 10.3 905 0.53 4.9 SDT[^(F)BT(2)]₂ 10.9 762 0.57 4.7SDT[PT(3)]₂ 1.9 808 0.33 0.5 SDT[PT(4)]₂ 11.3 822 0.47 4.4SDT[^(F)BT(4)]₂ 12.4 810 0.68 6.9 SDT[^(FF)BT(4)]₂ 10.8 909 0.56 5.5

While preferred embodiments of this invention have been shown anddescribed, modifications thereof can be made by one skilled in the artwithout departing from the spirit or teaching of this invention. Theembodiments described herein are exemplary only and are not limiting.Many variations and modifications of systems and methods are possibleand are within the scope of the invention. Accordingly, the scope ofprotection is not limited to the embodiments described herein, but isonly limited by the claims that follow, the scope of which shall includeall equivalents of the subject matter of the claims.

Should the disclosure of any patents, patent applications, andpublications which are incorporated herein by reference conflict withthe description of the present application to the extent that it mayrender a term unclear, the present description shall take precedence.

1. An electronic or optoelectronic device comprising a first electrode;a second electrode proximate the first electrode with a space reservedtherebetween; and an active layer arranged between and in electricalconnection with the first and second electrodes, wherein the activelayer comprises at least one dye compound, wherein the dye compoundcomprises a small molecule compound of Formula (I):T1a-T2a-(A1)_(m)-(B1)_(n)-P-(B2)_(n)-(A2)_(m)-T2b-T1b  (I) wherein P isan optionally substituted aryl group or an optionally substitutedheteroaryl group; or P is a group having the formula: -A1-P′-A2-,wherein P′ is an optionally substituted aryl group or an optionallysubstituted heteroaryl group; each B1 and each B2, independently, is anoptionally substituted thiophene; each A1 and each A2, independently, isan optionally substituted aryl group or an optionally substitutedheteroaryl group; T2a and T2b, independently, have the formula:

T1a and T1b, independently, have the formula:

wherein each R⁴, R⁵, R⁶, R⁷, and R⁸, independently, is H, halo, alkyl,haloalkyl, alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl,heteroaryl, or acyl; each R⁹, independently, is H, alkyl, or haloalkyl;each n, independently, is 0, 1, 2 or 3; each m, independently, is 1, 2,or 3; provided that at least one of R⁴ to R⁸ is halo or haloalkyl; andfurther provided that when R⁴ or R⁵ is fluoro, the other is not alkyl orhaloalkyl, and when R⁷ or R⁸ is fluoro, the other is not alkyl orhaloalkyl.
 2. The electronic or optoelectronic device of claim 1,wherein each of R⁴ to R⁸, independently, is H, fluoro, alkyl, orfluoroalkyl.
 3. The electronic or optoelectronic device of claim 1,wherein (i) each R⁶, independently, is alkyl, and at least one of R⁴,R⁵, R⁷, and R⁸ is fluoro, and the remaining of R⁴ to R⁸ are H or fluoro;or (ii) each R⁶, independently, is fluoro or haloalkyl, and each R⁴, R⁵,R⁷, and R⁸, independently, is H or alkyl.
 4. The electronic oroptoelectronic device of claim 1, wherein P or P′ is selected from thegroup consisting of

wherein each R₀₀, independently, is H or alkyl; and each i is 0, 1, 2,or 3; each A1 and each A2, independently, is selected from the groupconsisting of:

wherein each Q, independently, is O or S; each R₀, independently, is Hor alkyl; and wherein each T1a, T2a, A1, B1, B2, A2, T2b, T1b, n and mare selected such that the small molecule compound is symmetric about P.5. The electronic or optoelectronic device of claim 1, wherein P or P′has the formula:

wherein X is C, Si, or Ge; and each R₀₀, independently, is H or alkyl.6. The electronic or optoelectronic device of claim 1, wherein each A1and each A2, independently, is selected from the group consisting of:

wherein Q is O or S.
 7. The electronic or optoelectronic device of claim1, wherein each n is
 0. 8. The electronic or optoelectronic device ofclaim 1, having the formula:

wherein each Y and each Z, independently, is N or CR³; each R³,independently, is H, F, alkyl, or haloalkyl; and provided that Y-Z isnot CH—CH.
 9. The electronic or optoelectronic device of claim 1,wherein the small molecule compound of Formula (I) is selected from oneof:


10. A small molecule compound of Formula (I):T1a-T2a-(A1)_(m)-(B1)_(n)-P-(B2)_(n)-(A2)_(m)-T2b-Tb  (I) wherein P isan optionally substituted aryl group or an optionally substitutedheteroaryl group; or P is a group having the formula: -A1-P′-A2-,wherein P′ is an optionally substituted aryl group or an optionallysubstituted heteroaryl group; each B1 and each B2, independently, is anoptionally substituted thiophene; each A1 and each A2, independently, isan optionally substituted aryl group or an optionally substitutedheteroaryl group; T2a and T2b, independently, have the formula:

T1a and T1b, independently, have the formula:

wherein each R⁴, R⁵, R⁶, R⁷, and R⁸, independently, is H, halo, alkyl,haloalkyl, alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl,heteroaryl, or acyl; each R⁹, independently, is H, alkyl, or haloalkyl;each n, independently, is 0, 1, 2 or 3; each m, independently, is 1, 2,or 3; provided that at least one of R⁴ to R⁸ is halo or haloalkyl; andfurther provided that when R⁴ or R⁵ is fluoro, the other is not alkyl orhaloalkyl, and when R⁷ or R⁸ is fluoro, the other is not alkyl orhaloalkyl.
 11. The small molecule compound of claim 10, wherein each ofR⁴ to R⁸, independently, is H, fluoro, alkyl, or fluoroalkyl.
 12. Thesmall molecule compound of claim 10, wherein (i) each R⁶, independently,is alkyl, and at least one of R⁴, R⁵, R⁷, and R⁸ is fluoro, and theremaining of R⁴ to R⁸ are H or fluoro; or (ii) each R⁶, independently,is fluoro or haloalkyl, and each R⁴, R⁵, R⁷, and R⁸, independently, is Hor alkyl.
 13. The small molecule compound of claim 10, wherein P or P′is selected from the group consisting of

wherein each R₀₀, independently, is H or alkyl; and each i is 0, 1, 2,or 3; each A1 and each A2, independently, is selected from the groupconsisting of:

wherein each Q, independently, is O or S; each R₀, independently, is Hor alkyl; and wherein each T1a, T2a, A1, B1, B2, A2, T2b, T1b, n and mare selected such that the small molecule compound is symmetric about P.14. The small molecule compound of claim 10, wherein P or P′ has theformula:

wherein X is C, Si, or Ge; and each R₀₀, independently, is H or alkyl.15. The small molecule compound of claim 10, wherein each A1 and eachA2, independently, is selected from the group consisting of:

wherein Q is 0 or S.
 16. The small molecule compound of claim 10,wherein each n is
 0. 17. The small molecule compound of claim 10, havingthe formula:

wherein each Y and each Z, independently, is N or CR³; each R³,independently, is H, F, alkyl, or haloalkyl; and provided that Y-Z isnot CH—CH.
 18. The small molecule compound of claim 10, wherein thesmall molecule compound of Formula (I) is selected from one of:


19. An electronic or optoelectronic device comprising a first electrode;a second electrode proximate the first electrode with a space reservedtherebetween; and an active layer arranged between and in electricalconnection with the first and second electrodes, wherein the activelayer comprises at least one dye compound, wherein the dye compoundcomprises a small molecule compound of Formula (II):(T1a)-(T2a-T2a)_(y)-(B1)-(A1)_(j)-(B2)-(T2b-T2b)_(y)-(T1b)  (II) whereineach A1, independently, is selected from the group consisting of

wherein each Q, independently, is O or S; each R₀, independently, is Hor alkyl; each B1 and each B2, independently, is an optionallysubstituted thiophene; each T2a and each T2b, independently, have theformula:

each T1a and each T1b, independently, have the formula:

wherein each R⁴, R⁵, R⁶, R⁷, and R⁸, independently, is H, halo, alkyl,haloalkyl, alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl,heteroaryl, or acyl; each R⁹, independently, is H, alkyl, or haloalkyl;j is 1, 2, or 3; each x, independently, is 0, 1, or 2; each y,independently, is 1 or 2; provided that at least one of R⁴ to R⁸ is haloor haloalkyl.
 20. A small molecule compound of Formula (II):(T1a)-(T2a-T2a)_(y)-(B1)_(x)-(A1)_(j)-(B2)_(x)-(T2b-T2b)_(y)-(T1b)  (II)wherein each A1, independently, is selected from the group consisting of

wherein each Q, independently, is O or S; each R₀, independently, is Hor alkyl; each B1 and each B2, independently, is an optionallysubstituted thiophene; each T2a and each T2b, independently, have theformula:

each T1a and each T1b, independently, have the formula:

wherein each R⁴, R⁵, R⁶, R⁷, and R⁸, independently, is H, halo, alkyl,haloalkyl, alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl,heteroaryl, or acyl; each R⁹, independently, is H, alkyl, or haloalkyl;j is 1, 2, or 3; each x, independently, is 0, 1, or 2; each y,independently, is 1 or 2; provided that at least one of R⁴ to R⁸ is haloor haloalkyl.
 21. An electronic or optoelectronic device comprising afirst electrode; a second electrode proximate the first electrode with aspace reserved therebetween; and an active layer arranged between and inelectrical connection with the first and second electrodes, wherein theactive layer comprises at least one dye compound, wherein the dyecompound comprises a small molecule compound of Formula (III):(E)-(T2a-T2a)_(y)-(A2)_(z)-(P)_(x)-(A1)_(j)-(P)_(x)-(A2)_(z)-(T2b-T2b)_(y)-(E)  (III)wherein each P, independently, is an optionally substituted aryl groupor an optionally substituted heteroaryl group; each A1 and each A2,independently, is an optionally substituted aryl group or an optionallysubstituted heteroaryl group; each T2a and each T2b, independently, havethe formula:

wherein each R⁴ and R⁵, independently, is H, halo, alkyl, haloalkyl,alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl, heteroaryl,or acyl; each R⁹, independently, is H, alkyl, or haloalkyl; and each E,independently, is selected from the group consisting of:

wherein each Q, independently, is O or S; each R₀, independently, is Hor alkyl; each R₁₀, independently, is halo, —NO₂, —N₃, —CN, —OR₀, or R₀;wherein j is 1, or 2; each x, independently, is 0, 1, or 2; each y,independently, is 1 or 2; each z, independently, is 0, 1, or 2; providedeach A2, independently, is not A1; provided that at least one of R⁴ orR⁵ is halo or haloalkyl; and wherein each A1, A2, T2a, T2b, P, E, j, x,y, and z are selected such that the small molecule compound is symmetricabout A1.
 22. The electronic or optoelectronic device of claim 21,wherein each A1 and each A2, independently, are selected from the groupconsisting of:

wherein each Q, independently, is O or S; each R₀, independently, is Hor alkyl; and A1 is different from A2.
 23. The electronic oroptoelectronic device of claim 21 where each P, independently, isselected from the group consisting of:

wherein each R₀₀, independently, is H or alkyl.
 24. The electronic oroptoelectronic device of claim 21, wherein j=1 and x=1, and A1 and A2are selected from the group consisting of:


25. The electronic or optoelectronic device of claim 21, wherein P isselected from the group consisting of:

wherein X is C, Si, or Ge, and each R₀₀, independently, is H or alkyl.26. A small molecule compound of Formula (III):(E)-(T2a-T2a)_(y)-(A2)_(z)-(P)_(x)-(A1)_(j)-(P)_(x)-(A2)_(z)-(T2b-T2b)_(y)-(E)  (III)wherein each P, independently, is an optionally substituted aryl groupor an optionally substituted heteroaryl group; each A1 and each A2,independently, is an optionally substituted aryl group or an optionallysubstituted heteroaryl group; each T2a and each T2b, independently, havethe formula:

wherein each R⁴ and R⁵, independently, is H, halo, alkyl, haloalkyl,alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl, heteroaryl,or acyl; each R⁹, independently, is H, alkyl, or haloalkyl; and each E,independently, is selected from the group consisting of:

wherein each Q, independently, is 0 or S; each R₀, independently, is Hor alkyl; each R₁₀, independently, is halo, —NO₂, —N₃, —CN, —OR₀, or R₀;wherein j is 1, or 2; each x, independently, is 0, 1, or 2; each y,independently, is 1 or 2; each z, independently, is 0, 1, or 2; providedeach A2, independently, is not A1; provided that at least one of R⁴ orR⁵ is halo or haloalkyl; and wherein each A1, A2, T2a, T2b, P, E, j, x,y, and z are selected such that the small molecule compound is symmetricabout A1.
 27. The small molecule of claim 26, wherein each A1 and eachA2, independently, are selected from the group consisting of:

wherein each Q, independently, is O or S; each R₀, independently, is Hor alkyl; and A1 is different from A2.
 28. The small molecule compoundsof claim 26 where each P, independently, is selected from the groupconsisting of:

wherein each R₀₀, independently, is H or alkyl.
 29. The small moleculecompounds of claim 26, wherein j=1 and x=1, and A1 and A2 are selectedfrom the group consisting of:


30. The small molecule compounds of claim 26, wherein P is selected fromthe group consisting of:

wherein X is C, Si, or Ge, and each R₀₀, independently, is H or alkyl.31. An electronic or optoelectronic device comprising a first electrode;a second electrode proximate the first electrode with a space reservedtherebetween; and an active layer arranged between and in electricalconnection with the first and second electrodes, wherein the activelayer comprises at least one dye compound, wherein the dye compoundcomprises a small molecule compound of Formula (IV):(T1a)-(T2a)_(y)-(B1)_(x)-A3-(B2)_(x)-(T2b)_(y)-(T1b)  (IV) wherein eachA3, independently, is selected from the group consisting of

each R₀₀, independently, is H or alkyl; each Ar, independently, isselected from the group consisting of:

where Aryl=an aryl group; where HetAryl=a heteroaryl group; whereAryl^(F)=a fluorinated aryl group; where HetAryl^(F)=a fluorinatedheteroaryl group; where R^(F)=a fluorinated alkyl group; where X═F, Cl,Br, I, OR₀, SR₀, NHR₀, NR₀R₀, or R₀; where R₀═H or alkyl; each B1 andeach B2, independently, is an optionally substituted thiophene; each T2aand each T2b, independently, have the formula:

each T1a and each T1b, independently, have the formula:

wherein each R⁴, R⁵, R⁶, R⁷, and R⁸, independently, is H, halo, alkyl,haloalkyl, alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl,heteroaryl, or acyl; each R⁹, independently, is H, alkyl, or haloalkyl;each x, independently, is 0, 1, or 2; each y, independently, is 1 or 2;provided that at least one of R⁴ to R⁸ is halo or haloalkyl.
 32. Theelectronic or optoelectronic device of claim 31, where each A1,independently, is selected from the group consisting of

each R₀₀, independently, is H or alkyl; each Ar, independently, isselected from the group consisting of:

where Aryl=an aryl group; where HetAryl=a heteroaryl group; whereAryl^(F)=a fluorinated aryl group; where HetAryl^(F)=a fluorinatedheteroaryl group; where R^(F)=a fluorinated alkyl group; where X═F, Cl,Br, I, OR₀, SR₀, NHR₀, NR₀R₀, or R₀; where R₀═H or alkyl.
 33. Theelectronic or optoelectronic device according to claim 31, having theformula


34. The electronic or optoelectronic device according to claim 31,having the formula


35. A small molecule compound of Formula (IV):(T1a)-(T2a)_(y)-(B1)-A3-(B2)_(x)-(T2b)_(y)-(T1b)  (IV) wherein each A3,independently, is selected from the group consisting of

each R₀₀, independently, is H or alkyl; each Ar, independently, isselected from the group consisting of:

where Aryl=an aryl group; where HetAryl=a heteroaryl group; whereAryl^(F)=a fluorinated aryl group; where HetAryl^(F)=a fluorinatedheteroaryl group; where R^(F)=a fluorinated alkyl group; where X═F, Cl,Br, I, OR₀, SR₀, NHR₀, NR₀R₀, or R₀; where R₀═H or alkyl; each B1 andeach B2, independently, is an optionally substituted thiophene; each T2aand each T2b, independently, have the formula:

each T1a and each T1b, independently, have the formula:

wherein each R⁴, R⁵, R⁶, R⁷, and R⁸, independently, is H, halo, alkyl,haloalkyl, alkoxy, alkenyl, alkynyl, thioalkyl, —NHR⁹, —N(R⁹)₂, aryl,heteroaryl, or acyl; each R⁹, independently, is H, alkyl, or haloalkyl;each x, independently, is 0, 1, or 2; each y, independently, is 1 or 2;provided that at least one of R⁴ to R⁸ is halo or haloalkyl.
 36. Thesmall molecule compound of claim 35, where each A1, independently, isselected from the group consisting of

each R₀₀, independently, is H or alkyl; each Ar, independently, isselected from the group consisting of:

where Aryl=an aryl group; where HetAryl=a heteroaryl group; whereAryl^(F)=a fluorinated aryl group; where HetAryl^(F)=a fluorinatedheteroaryl group; where R^(F)=a fluorinated alkyl group; where X═F, Cl,Br, I, OR₀, SR₀, NHR₀, NR₀R₀, or R₀; and where R₀═H or alkyl.
 37. Thesmall molecule compound according to claim 35, having the formula


38. The small molecule compound according to claim 35, having theformula